A US researcher claims to have found stem cells in adults that are as versatile as embryonic stem cells.

This week's New Scientist reports that it has seen a patent application indicating Catherine Verfaillie, of the University of Minnesota, has carried out extensive experiments to confirm the claim.

Verfaille is reported to have extracted cells dubbed multipotent adult progenitor cells (MAPCs) from the bone marrow of adult mice, rats, and humans, and shown they can grow indefinitely in culture without ageing.

She also reports the cells could be turned into muscle, cartilage, bone, liver, and different types of neurons and brain cells.

According to Dr Tony Dodds, Director of Haematology and Stem Cell Transplantation at Sydney's St Vincents Hospital, the research, if confirmed, could be significant.

He was particularly interested in Verfaille's use of bone marrow cells, saying that it promised an easily accessible source of multipotent stem cells.

"We already do sixty bone marrow transplants a year," he said. "This could simply be an extension of existing techniques."

Such transplants involve the removal of stem cells from the bone marrow which can then be transplanted to provide the recipient with a source of blood and immune cells.

The stem cells reportedly extracted by Verfaille are even more versatile than the cells typically used in transplants. Theoretically, they could be harvested to provide perfectly-matched replacement tissues and organs without the need for therapeutic cloning or genetic engineering of stem cells from human embryos.

Scientists' use of embryonic stem cells  usually obtained from embryos left over from IVF programs and donated for research  is controversial, and subject to restrictions in most countries, including Australia.

If research into adult stem cells proves promising, it will no doubt add to questions over whether embryonic stem cell research is necessary.

Firstly, however, Dr Dodds said it was important to confirm that the apparent versatility of the cells was not due to contaminants in the culture from other tissues.

According to New Scientist, Verfaille used a technique called 'retroviral marking' to prove that the descendants of a single cell could turn into a variety of different cell types, and showed the same in developing mice.

Dr Dodds, however, said that detecting markers in itself did not indicate that the multipotent adult progenitor cells formed functioning cells. He said it was also important to show that a cell line could divide to provide enough volume to be used in organ transplants or tissue repair.

Most importantly, however, Verfaille's findings need to be confirmed, and this in itself is a challenge.

"Until it's published no one can really confirm it," said Dr Dodds.

"Unfortunately because of patents, such research is often not published or even presented."